There has been a recent change in the contemporary technology in dry toner laser printers, copiers and facsimile machines. The old corolla assemblies with their generated high ozone emission levels and high frequency of corona related streaks are largely being replaced with charge roller assemblies. With this recent shift in technology, many unsolved problems have been cropping up, particularly with the first versions, particularly the CANON NX engine as used in the very popular HP LASERJET IIISi and the CANON LX engine as used in the HP LASERJET IIP, IIIP and CANON L-700 series facsimile machines. These problems occur particularly in the laser cartridge remanufacturing industry where these toner cartridges are currently becoming very popular. Among the problems largely reported by these "remanufacturers" as they are sometimes called are grey background haze, reverse double imaging related to the fuser roller, normal double-imaging caused by the primary charge roller (PCR) charge roller aging and degradation, and charge roller contact problems. Many toner cartridges recently available on the market experience the outlined problems to varying degrees. Also, with most cartridges, a reported white powder electrostatically sticks to the primary charge roller or PCR, causing more problems at the end of the recharge cycle when the toner cartridge is near empty and needs to be remanufactured, leaving a white residue on the PCR.
Another problem is the instability of the primary charge roller's physical location as it rotates. The PCR rotates in two saddles and may shift position along its longitudinal centerline, causing a less smooth electrostatic charge and hampering the quality of the image. The instability of the charge roller's physical location also causes increased wear of the saddles after continued use and many cycles, allowing the PCR to also wobble front to back in the saddles. One of the plastic saddles is electrically conductive and does not function as well as it should in helping to transfer the electrostatic charge from the PCR to the photoreceptor drum.
One solution to this problem commonly used by the remanufacturers is to put a conductive grease in the end-saddle for better electrical flow and improved lubrication causing slower wear. This has been an improvement, but has not eliminated the electrical problems experienced. Part of the problem is that the charging of the photoreceptor by the PCR is poor. Another part of the problem is that the erasure of the previous image on the photoreceptor drum, in which the PCR is in contact, is incomplete as a result of the lack of a better electrical connection of the PCR that thereby charges the photoreceptor drum with an incomplete charge. This causes a "ghosting" or double-imaging on the output page. Ghosting is when a part of the previous image or a "ghost" of the previous image appears one or more drum rotations later, and has interfered with the current image. In this case the ghosting is caused by improper erasure of the previous image which stays residually on the photoreceptor drum caused by poor charging of the photoreceptor drum. Also, the PCR must be flush against the photoreceptor drum. If the PCR moves, it can cause more print quality problems.
It should be disclosed that after the invention disclosed in this application was made, the new HP SERIES 4 printer came out with a device in the toner cartridge assembly which attempted to make the location of the PCR more stable by reducing the described wobble. The invention of this application was invented long before the HP version, yet within one year of the filing date of this application. Furthermore, the HP version does not use a flat-spring-contact device at each end of the charge roller. The device used by HP is shaped like a double prong and used at only one end of the charge roller. One HP device (CANON NX printer engine) is made of an alloy that appears to be stainless steel, so it does not improve the electricity flow to the PCR as much. The HP version is believed to be far inferior to this invention. The HP version uses metal at one end and a plastic stop which is a part of the plastic assembly, not modular, at the other. With a plastic non-modular stop at one end, the life of the toner cartridge is limited so more brand-new toner cartridges will be used. With the device of this invention, a clip is used at each end, so if the clips wear, they may be replaced indefinitely for a toner cartridge that may be repaired as long as the other components are usable. With the HP clips, the clip is continuous with the contact strip to the printer, where the cartridge connects electrically to the printer, as one component. With the device of this invention, the clips were designed to be added on for toner cartridges that do not have clips already as an add-on. An improved toner cartridge may now be made as a result, with longer life and may be recycled. The differences between the invention of this application and the HP version will be made clear from the Complete Description. Furthermore, the device of this invention was designed as an "add on" to improve an existing laser printer cartridge lacking in this device, wheras the HP device is one that goes in the brand new cartridge. That is not to say that this device can't go into a brand new cartridge because it may universally go into either.